ci-tooling/ci/jobgenerator.py

#!/usr/bin/env python3

# Copyright (C) 2019 Simon Quigley <tsimonq2@lubuntu.me>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import git
import jenkinsapi
from os import getenv
from yaml import CLoader
from yaml import load as yaml_load
from jinja2 import Template
from shutil import rmtree
from tempfile import mkdtemp
from jenkinsapi.jenkins import Jenkins

class Generator:
    def clone_metadata(self):
        """Clone the metadata repository using the values set in the env vars

        The METADATA_URL and METADATA_REPO_NAME env vars must be set to use
        this function.

        The repository must have a ci.conf file in YAML format.

        This uses Git to clone the given repository - other VCSes are not
        supported at this time.
        """

        # Assuming this is ran inside Jenkins, this fetches the env vars set in
        # the job config. If those don't exist, we need to throw an error,
        # because otherwise we have no metadata to actually pull from
        metadata_url = getenv("METADATA_URL")
        metadata_repo_name = getenv("METADATA_REPO_NAME")
        if not metadata_url or metadata_url == "" or not metadata_repo_name \
            or metadata_repo_name == "":
            raise ValueError("METADATA_URL and METADATA_REPO_NAME must be set")

        # Create a temporary directory in the most secure manner possible and
        # clone the metadata, throwing the directory away when we're done
        try:
            metadata_loc = mkdtemp()
            git.Git(metadata_loc).clone(metadata_url)

            # Load ci.conf and parse it
            with open(metadata_loc + "/" + metadata_repo_name + "/ci.conf") \
                as metadata_conf_file:
                metadata_conf = yaml_load(metadata_conf_file, Loader=CLoader)
        finally:
            rmtree(metadata_loc)

        return metadata_conf

    def parse_metadata(self):
        """Parse the data pulled from clone_metadata

        Allow the user to be able to set default key values, resulting in
        shorter and cleaner configuration files.
        """

        metadata_conf = self.clone_metadata()
        metadata_req_keys = ["name", "packaging_url", "packaging_branch",
                             "upload_target", "releases", "default_branch"]
        metadata_opt_keys = ["upstream_url", "upstream_branch"]

        for package in metadata_conf["repositories"]:
            # Load defaults in if they're not there, ignore the optional ones
            for mkey in metadata_req_keys:
                if not mkey in package and mkey in metadata_conf["default"]:
                    package[mkey] = metadata_conf["default"][mkey]
            # Don't proceed if any of the keys in the config are invalid
            for mkey in package:
                if not mkey in metadata_req_keys and not mkey in \
                    metadata_opt_keys:
                    raise ValueError("Invalid key present:", mkey)

        return metadata_conf["repositories"]

    def auth_jenkins_server(self):
        """Authenticate to the Jenkins server

        This involves use of the API_SITE, API_USER, and API_KEY variables
        set in Jenkins. These need to be private, so they are defined in the
        system-wide Jenkins credential storage.
        """
        # Load the API values from the environment variables
        api_site = getenv("API_SITE")
        api_user = getenv("API_USER")
        api_key = getenv("API_KEY")
        for envvar in [api_site, api_user, api_key]:
            if not envvar or envvar == "":
                raise ValueError("API_SITE, API_USER, and API_KEY must be",
                                 "defined")
        # Authenticate to the server
        server = Jenkins(api_site, username=api_user, password=api_key)

        return server

    def load_config(self, job_type, data):
        """Return a template that is a result of loading the data

        This makes it easier to standardize several types of jobs
        """

        # The template name should always correspond with the job type
        # Regardless of the job type, there should always be a template
        with open("templates/" + job_type + ".xml") as templatef:
            template = ""
            for text in templatef.readlines():
                template += text
            template = Template(template)

        url = data["packaging_url"]
        branch = data["packaging_branch"]

        if job_type == "package":
            upstream = data["upstream_url"]
            upload_target = data["upload_target"]
            package_config = template.render(PACKAGING_URL=url,
                                             PACKAGING_BRANCH=branch,
                                             UPSTREAM_URL=upstream,
                                             NAME=data["name"],
                                             RELEASE=data["release"],
                                             UPLOAD_TARGET=upload_target)
        elif job_type == "merger":
            default_branch = data["default_branch"]
            package_config = template.render(PACKAGING_URL=url,
                                             PACKAGING_BRANCH=branch,
                                             NAME=data["name"],
                                             DEFAULT_BRANCH=default_branch)
        else:
            raise ValueError("Invalid job type")

        return package_config

    def create_jenkins_jobs(self):
        """Interface with Jenkins to create the jobs required

        This uses the Jenkins API to do the following tasks:
         1. Assess which jobs are currently defined and if the jobs defined
            in the metadata overlap with those, do an update of the job config
            to match the current template.
         2. If there are new jobs defined, create them. If there are jobs no
            longer defined, remove them.
         3. Update the per-release views to ensure the jobs are in the correct
            views. If there are any releases no longer defined, remove them.
        """

        # Authenticate to the Jenkins server
        server = self.auth_jenkins_server()

        # Iterate through the packages we have in our metadata and update the
        # job config for each if they match. If there's no existing job found,
        # just create it
        metadata = self.parse_metadata()
        jobs = []
        releases = set()

        for job_name, job_instance in server.get_jobs():
            jobs.append(job_name)

        for package in metadata:
            # Create the merger jobs first
            job_name = "merger_" + package["name"]
            package_config = self.load_config("merger", package)
            # TODO: This is duplicate code, and it should be consolidated
            if job_name in jobs:
                job = server.get_job(job_name)
                job.update_config(package_config)
            else:
                job = server.create_job(job_name, str(package_config))
                if "merger" in server.views:
                    view = server.views["merger"]
                else:
                    view = server.views.create("merger")
                view.add_job(job_name)

            for release in package["releases"]:
                job_name = release + "_" + package["name"]
                # Load the config given the current data
                package["release"] = release
                package_config = self.load_config("package", package)
                if job_name in jobs:
                    job = server.get_job(job_name)
                    job.update_config(package_config)
                else:
                    job = server.create_job(job_name, str(package_config))
                    # With an existing job we can assume it's already in an
                    # appropriate view. With new jobs, we should see if the
                    # view exists, and if it doesn't, create it
                    if release in server.views:
                        view = server.views[release]
                    else:
                        view = server.views.create(release)

                    view.add_job(job_name)


if __name__ == "__main__":
    generator = Generator()
    print(generator.create_jenkins_jobs())